Mercury alert: Is canned tuna safe to eat?
The tuna sandwich is a lunchbox staple. But several species of tuna, like other large ocean fish, contain higher-than-average amounts of mercury.
This is of particular concern for young children, whose nervous system, brain, heart, kidneys and lungs are all susceptible to the harmful effects of mercury.
But parents and kids need not give up tuna altogether.
How much canned tuna is safe to eat?
There are two main kinds of canned tuna: chunk light and solid or chunk white (albacore). Most canned white tuna is albacore. Its mercury levels are almost three times higher than the smaller skipjack, used in most canned light tuna.
These recommendations are based on EPA guidance and estimates of mercury in the most popular canned tunas:
- Canned white, or albacore (0.32 parts per million of mercury). Children under six can eat up to one 3-ounce portion a month; children from 6–12, two 4.5-ounce portions a month. Adults, including pregnant women, can safely eat it up to three times a month (women, 6-ounce portions; men, 8-ounce portions).
- Canned light — the safer choice (0.12 parts per million of mercury). Children under six can eat up to three 3-ounce portions per month. Older children and adults can safely eat it once a week. But look out for “gourmet” or “tonno” labels. They are made with bigger yellowfin tuna and can contain mercury levels comparable to canned white.
- A better alternative is canned salmon (mostly sockeye or pink from Alaska), which is low in contaminants and high in heart-healthy omega-3s. It's also sustainably caught in Alaska and similarly priced, making it a great choice all around.
Keep an eye on school lunches
If your child eats tuna in school lunches, it's best to find
out what types are being offered and how often.
A study by the Mercury Policy Project found a wide range of mercury levels in both light and white tuna from government sponsored school lunch programs. Some of the canned albacore/white tuna tested had mercury levels almost four times the average level reported by FDA.
For health warnings about other fish, see our Seafood Selector.
Stop mercury from getting into tuna
How does mercury get into fish to start with? It is emitted into the air by coal-fired power plants and other industrial sources. It rains down on rivers, lakes and oceans.
Once in the water, mercury gets into the tissues of marine animals. It builds up as big fish eat smaller fish, so top predators like tuna, king mackerel and swordfish are the most contaminated.
Stopping mercury air pollution is essential to keeping fish safe to eat.